This invention relates generally to crop gathering attachments for crop harvesting machines and, more specifically, to a crop conveying mechanism utilized in a crop harvesting header.
It is usual in crop harvesting machines for standing crop to be harvested by first cutting it and then feeding the cut crop to crop processing components such as a threshing and separating mechanism in the case of a combine harvester, or a chopper in the case of a forage harvester, for example. The feeding of the cut crop to the crop processing components needs to be fluent and consistent so as to load those components uniformly and hence maximize the capacity of the machine. In some known machines, a conveying and consolidating mechanism, such as an auger, for feeding the cut crop to the crop processing components are located a relatively short distance behind the cutterbar, which is desirable from the standpoint of positively moving the crop to the processing means immediately after it has been cut, but which gives rise to the problem, in some instances, of crop being acted upon by the feeder means before it is cut and thus being pulled. This particular problem tends to happen when harvesting crop having long stalks (such as rye and rape for example) which is not standing upright due to adverse weather conditions.
Another problem experienced with known machines arises when the crop is wet and/or infested with weeds. With crop in either of these conditions, the problem of achieving a fluent flow continues to exist as there is a tendency for crop to accumulate in a dead spot which inevitably exists between the cutter means and feeder means even if a reel is used to help sweep the crop first to the cutter means and thence to the feeder means.
One solution to this problem is to employ a conveying device between the cutter means and the feeder means. One such device is a draper such as is disclosed in U.S. Pat. No. 4,038,809. Since the draper separates the cutter and the normal feeder means and is itself not as aggressive as the latter, the aforementioned problem of pulling long-stalked crops before they are cut, is avoided. Also, the problem associated with the dead spot in which wet or weed-infested crop tends to accumulate is relieved.
However, the draper is in effect a continuous belt conveyor, usually made of canvas, and it is difficult to provide adequate tracking means without using complicated, and hence expensive, components for the belts. Furthermore, crop material tends to wrap around the ends of the shafts carrying the canvas belt and eventually gets between the belt and the shafts. This, together with inadequate tracking, results in excessive wear taking place relatively quickly, resulting in frequent belt replacement. Accordingly, the draper has not become a universally accepted device.
British Patent Specification No. 2,094,606A discloses a crop gathering attachment for a crop harvesting machine which incorporates some of the advantages of a draper and avoids many of the disadvantages thereof. The disclosed attachment utilizes an additional feeder mechanism disposed between the normal cutterbar and the normal feeder. The additional feeder mechanism includes a plurality of rotary members, each in the form of shaft on which are mounted a plurality of crop conveying elements extending from the shaft in relatively close proximity, each shaft extending transversely of the attachment and being spaced relative to each other so that the crop conveying elements of adjacent rotary members interleave. In use, the rotary members are rotated in the same direction so that they constitue in effect a moving floor operable to transfer crop from the cutterbar generally longitudinally of the attachment to the normal feeder. These crop conveying elements may be in the form of fingers spaced axially of and equiangularly around the associated shaft or in the form of a plurality of disc members or flanges spaced along the shaft.
While this arrangement has been found very satisfactory for most crops and crop conditions, it does not always handle rice and rape seed, for example, in the best possible manner. In the case of rape seed, a comparatively large amount of grain can fall loose as soon as the crop has been cut and the crop conveying disc members or fingers of the arrangement of British Specification No. 2,094,606A do not always convey that grain to the normal feeder means for subsequent processing. In the case of rice, sticky debris and straw may fill up the spaces between the disc members and cause plugging.